Through the letterbox, around a swollen sash, under a tired front door, it sneaks in and sits on your ankles. You nudge the thermostat, then the bill nags at the back of your head. The quick fix you need isn’t another jumper. It’s sealing the gap that’s stealing your heat.
The other night I stood barefoot in a rented London flat, listening to the wind rattle the bins like an overexcited drummer. The radiators were on, but the room had that thin, unsettled chill — warm in patches, cold round the edges. I knelt by the living-room window, peeled a strip of foam, pressed it along the frame and shut the sash. The room hushed. It wasn’t dramatic, just a gentle stillness, like someone had shut a door three rooms away. It felt like the flat exhaled. It took five minutes.
The tiny gap that drains your heat
Draughts don’t roar, they whisper. You feel them as a tickle on your wrists when you type, as a chill that lives at skirting-board height, as radiators that never quite “win”. In older buildings, gaps become part of the architecture — a letterbox without a brush, a lock that plays chimney, a door that never met a threshold it couldn’t ignore. Warm air drifts out, cold air draws in, and the boiler works overtime like a musician playing to an open field.
I tested this in a friend’s Hackney flat on a January evening. We did the old-school candle trick, holding a flame near the frame and watching it flicker sideways at the meeting rail. A cheap digital thermometer on the coffee table read 19.4°C; near the leaky window, it fell to 17.7°C in minutes. After a quick foam strip and a rolled towel at the door, the edge-of-room chill eased. By bedtime, the living space held steady at 19°C without nudging the thermostat. Not a miracle. A nudge in the right direction.
When air leaks, your home turns into a slow-motion exchange system. Warm air rises and escapes at the top, pulling cold air in low down to replace it — the stack effect in action. Those little gaps accelerate the cycle like a cracked car window on the motorway. Close the pathways and you slow the invisible conveyor belt, which calms the room and evens the temperature. You still want fresh air for health, especially in the kitchen and bathroom, yet you don’t need a gale through the lounge. Think steer and sift, not block and box-in.
The five-minute fix: peel, stick, toast
The fastest route to a warmer flat is a **self-adhesive foam strip** along the bits that move: doors and windows. Wipe the contact area dry, cut the strip to length, and press it where frame and sash meet, or where a door kisses its stop. If the gap under the door is the villain, slide a draught excluder across or roll a towel into an instant “sausage”. For letterboxes, a brush-style cover snaps on in seconds. Do one window, then sit. Feel the air calm. Repeat where it makes the most difference, not everywhere at once.
Go for the goldilocks fit: snug, not squashed. If the foam’s too thick, the door won’t latch; too thin and the wind still wins. Clean surfaces matter more than fancy products — a quick degrease helps it bond. Tenants often worry about marks; low-tack painter’s tape under the strip can make removal kinder. Keep kitchens and bathrooms breathing through trickle vents or scheduled window time, or you’ll swap draughts for damp corners. Let’s be honest: nobody really does this every day. Aim for better, not perfect.
There are a few errors to dodge and a couple of tricks that feel like cheating. Don’t wrap or tape over gas appliance vents, and keep a carbon monoxide alarm awake. If your sash rattles, a thin V-seal along the meeting rail tames the wobble without gluing anything shut. A simple **paper test** helps: shut a strip of paper in the door; if it slides out easily, the gap needs attention. As one housing engineer told me:
“Warm homes are built at the edges. Fix the edges and the middle looks after itself.”
Keep a mini kit by the broom cupboard so you actually use it:
- 5 m roll of foam or rubber draught strip
- Scissors and a clean cloth
- Painter’s tape for renter-friendly removal
- Letterbox brush and a door ‘sausage’
What changes when the edges are sealed
Warmth stops being a fight. The boiler or heat pump cycles less frantically, the room warms more evenly, and that odd cold zone by the sofa fades. You wake to a flat that still feels settled, not shocked by the morning. Cups of tea stay hot a shade longer. Plants sulk less near the bay window. We’ve all had that moment when you step out of bed and the floor bites back — taming the edges turns that bite into a tap on the shoulder. Share it with a neighbour, trade tips, compare bills. The fix costs less than a takeaway and pays you back in quiet ways.
| Point clé | Détail | Intérêt pour le lecteur |
|---|---|---|
| Find the worst gap first | Do a candle or tissue test around frames, letterboxes and door bottoms | Targets five minutes where it actually warms the room |
| Use foam strip smartly | Snug fit along meeting points; add a door “sausage” for floor gaps | Instant comfort boost with a cheap, reversible fix |
| Keep healthy ventilation | Leave trickle vents open in wet rooms; never cover appliance vents | Stays toasty without inviting condensation or risk |
FAQ :
- Will draught-proofing cause condensation?Done right, no. Seal the leaky lounge and bedrooms, but let kitchens and bathrooms breathe via trickle vents or brief window time to flush moisture.
- How long does foam strip last?Good quality strips can hold for a season or two; rubber or silicone types last longer. If it compresses flat or peels, replace in minutes.
- Is this allowed in a rental?Most landlords are fine with reversible fixes. Use painter’s tape as a base if you’re worried about residue, and keep all packaging for move-out.
- What if my sash windows still rattle?Try thin V-seal along the meeting rails and parting beads. For big rattles, add a secondary film kit on the inside during winter for an extra buffer.
- Will this actually lower my bills?It trims wasted heat, which helps bills glide down rather than jump. The bigger the gaps you silence, the more your boiler or heater can relax.
